Could the eagles use a rookie RB?

Brian Westbrook by far is one of the most lethal weapons in the NFL. He is a triple threat Running Back, he can run, catch, and block what every team wants in their RB. But could the Eagles use a new rookie RB. In my opinion yes they could. With the 21st pick in the draft, Eagles can get a great rookie RB. Knowshon Moreno is probably already going to be gone, but what we need is a big power back that can get us that first down on 3rd and 3 and a touchdown on 2nd and goal. There are a couple backs in the draft that we can pick up, like Beanie Wells from Ohio State who is a big back with an impressive forty and can certainly get the job done. Shonn Green from Iowa who is a very big, powerful back with an impressive 4.6 forty who would fit perfect with the eagles offense. These are just some of my thoughts, what do you think?